This will be needed soon in order to retrieve the per-target
struct.

Cc: linux-scsi@vger.kernel.org
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NWanlong Gao <gaowanlong@cn.fujitsu.com>
Reviewed-by: NAsias He <asias@redhat.com>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>